Middle-aged adults are exercising more and living longer, but new research from the University of British Columbia suggests that even the fittest among them are not immune to cardiovascular disease—and they often don’t have any symptoms.

The study, published in BMJ Open Sport and Exercise Medicine, highlights how important it is for middle-aged athletes to have their doctor check their cardiovascular risk factors, especially if they have high blood pressure, high cholesterol or a family history of cardiovascular disease.

Cardiovascular disease refers to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke.

“We all know that exercise is good for us—it can help prevent a range of health problems and diseases, from cancer to depression,” said Barbara Morrison, the study’s lead author and a PhD student in experimental medicine at UBC. “However, even if you are really active, our findings suggest that you still can’t outrun your risk factors.”

For the study, researchers followed 798 “masters athletes”—adults aged 35 and older who engage in moderate to vigorous physical activity at least three days a week. The participants included a range of athletes, from runners to cyclists, triathletes, rowers and hockey players.

Participants were asked a range of questions about their health, family history and physical activity levels. They also had their blood pressure checked and waist circumference measured. Some participants also took part in an exercise stress test. Those with abnormal results underwent further testing, such as a CT coronary angiogram, to determine if they had cardiovascular disease.

Of the 798 athletes, 94 (11 per cent) were found to have significant cardiovascular disease. Ten participants were found to have severe coronary artery disease (a blockage in their artery of 70 per cent or greater) despite not having any symptoms.

This study’s findings build on previous research that found masters athletes have a higher incidence of cardiovascular disease than non-athletes of the same age with similar risk factors. However, previous research has also found that, compared to non-athletes, masters athletes typically have more calcified plaque, which is known to be more stable and less likely to cause a heart attack.

While the findings may seem alarming, Morrison emphasized that it doesn’t mean masters athletes should stop exercising.

She recommends people see their doctor for regular check-ups, including blood pressure and cholesterol monitoring, especially if they have a family history of heart attack or stroke.

“The good news is that cardiovascular disease is treatable,” she said. “Medication has been proven to reduce mortality risk, and even more so in people who are active.”

Practicing moderation when it comes to exercise is also important, she added. “There is no evidence that pushing exercise to the limit will make you live longer or your heart stronger, but when taken to the extreme, it may have the potential to do harm,” said Morrison. “You should never push yourself so hard that you can’t exercise the next day.”

The study—co-authored by researchers at SportsCardiologyBC, B.C. Children’s Hospital and Weill Cornell Medical College in New York—was funded by Mitacs Canada and the Canadian Institutes of Health Research.